Cloning and characterization of hOGG1, a human homolog of the OGG1 gene of Saccharomyces cerevisiae
Cloning and characterization of hOGG1, a human homolog of the OGG1 gene of Saccharomyces cerevisiae
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DOI：
10.1073/pnas.94.15.8010
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发表时间：
1997-07-22
影响因子：
11.1
通讯作者：
Boiteux, S
中科院分区：
文献类型：
--
作者：
Radicella, JP;Dherin, C;Boiteux, S
酵母菌属的OCG 1基因编码DNA糖基化酶活性，其是来自大肠杆菌的Fpg蛋白的功能类似物，并从受损的DNA中切除7，8-二氢-8-氧代鸟嘌呤（8-oxoG）。这种普遍存在的氧化损伤的修复对于防止细菌和酵母中的突变是必不可少的。鉴定了携带与酵母蛋白同源的ORF的人cDNA克隆，预测的蛋白质具有345个氨基酸，分子量为39 kDa。该蛋白与酵母Ogg 1蛋白具有38%的序列同一性，将这种新的人类基因产物添加到不断增长的酶家族中，该酶家族修复氧化损伤的碱基并与E.大肠杆菌内切酶III的表达，北方杂交分析表明该基因定位于染色体3 p25，在人体组织中广泛表达。大肠杆菌菌株，携带破坏的fpg基因，OGG 1的细菌功能类似物。这些培养物的无细胞提取物对携带8-oxoG/C碱基对的双链体DNA显示出特异性裂解酶活性，反应产物与酵母Ogg 1所显示的酶活性一致。底物特异性的分析揭示了对含有8-oxoG/C碱基对的DNA片段的非常强烈的偏好，特异性的模式与酵母酶的模式很好地相关。此外，当人编码序列在OGG 1的酵母菌株突变体中表达时，它能够补充自发增变子表型。这些结果使这个肚脐基因（hOGG 1）的酵母OGG 1的人类同源物的一个强有力的候选人，并建议其产品在保护基因组的氧化损伤嘌呤的诱变作用的重要作用。
The OCG1 gene of Saccharomyces criticise encodes a DNA glycosylase activity that is a functional analog of the Fpg protein from Escherichia coli and excises 7,8-dihydro-8-oxoguanine (8-oxoG) from damaged DNA. The repair of this ubiquitous kind of oxidative damage is essential to prevent mutations both in bacteria and in yeast, A human cDNA clone carrying an ORF displaying homology to the yeast protein was identified, The predicted protein has 345 amino acids and a molecular mass of 39 kDa. This protein shares a 38% sequence identity with the yeast Ogg1 protein, adding this novel human gene product ttl the growing family of enzymes that the repair of oxidatively damaged bases and are related to the E. coli endonuclease III, Northern blot analysis indicates that this gene, localized to chromosome 3p25, is ubiquitously expressed in human tissues, The cloned coding sequence was expressed in an E. coli strain that carried a disrupted fpg gene, the bacterial functional analog of OGG1. Cell-free extracts from these cultures displayed a specific lyase activity on duplex DNA that carried an 8-oxoG/C base pair, The products of the reaction are consistent with an enzymatic activity like the one displayed by the yeast Ogg1. Analysis of the substrate specificity reveals a very strong preference for DNA fragments harboring 8-oxoG/C base pairs, The pattern of specificity correlates well with the one found for the yeast enzyme, Moreover, when the human coding sequence was expressed in a yeast strain mutant in OGG1 it was able to complement the spontaneous mutator phenotype. These results make this navel gene (hOGG1) a strong candidate for the human homolog of the yeast OGG1 and suggest an important role of its product in the protection of the genome from the mutagenic effects of the oxidatively damaged purines.